An evaluation of formability using micro-embossing on an ultrafine-grained magnesium AZ31 alloy processed by high-pressure torsion

¹ Key Laboratory of Micro-systems and Micro-structures Manufacturing, Ministry of Education, Harbin Institute of Technology, Harbin 150080, China
² School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001, China
³ Departments of Aerospace & Mechanical Engineering and Materials Science, University of Southern California, Los Angeles, CA 90089-1453, USA
⁴ Materials Research Group, Faculty of Engineering and the Environment, University of Southampton, Southampton SO17 1BJ, UK

^a Corresponding author: e-mail: xjhit@hit.edu.cn

Abstract

An ultrafine-grained (UFG) magnesium AZ31 alloy was achieved with an average grain size of ∼200 nm by high-pressure torsion (HPT) at room temperature (RT) under a pressure of 6.0 GPa through 5 turns. Micro-embossing tests were conducted in a V-groove die having a width of 100 μm in the temperature range of 298 to 523 K. The formability of UFG AZ31 alloy was evaluated by measuring the percentage of material flowing into the V-groove. The results show that refinement of grain size can significantly improve the formability by increasing the stain rate sensitivity by comparison with the as-drawn AZ31 alloy. The results demonstrate that the UFG AZ31 alloy exhibits excellent formability for fabricating MEMS components with complicated structures.